Antarctica’s ice shelves are constantly changing, responding to even the most minuscule of temperature shifts. This 70-mile long rift in the Larsen C ice shelf could lead to its demise, though. The fracture measures more than 300 feet wide and about a third of a mile deep. NASA reports that the crack extends completely through the ice shelf but does not (yet) go all the way across it. Once the crack grows to that extent, an enormous portion of the ice shelf will calve off into the ocean, producing “an iceberg roughly the size of the state of Delaware.” That’s approximately 2,491 square miles or between nine and 12 percent of the total area of the ice shelf.

Elsewhere in Antarctica, other ice shelves are suffering smaller cracks that will have similarly huge impacts. Among the most immediate concerns is the safety of British Antarctic Survey’s Halley VI research station, which is currently situated about 4.3 miles from a crack in the Brunt ice shelf. BAS announced today the station will be moved in order to avoid becoming cut off from the rest of the ice shelf when the crack finally cuts across the entire shelf. Although moving a research station is no small feat, the team is optimistic and even “excited by the challenge,” as Tim Stockings, BAS director of operations, said in a statement. The station has been in its current location since 2012, and Stockings insists that it will remain operational with minimal disruption during the move.

NASA’s Operation IceBridge will continue to monitor the growth of the rifts, as part of its larger objective to collect data on changing polar land and sea ice, in keeping with previous measurements. The mission is currently funded through 2019.